Remove mjData.qLDiagSqrtInv, add corresponding argument to mj_solveM2.

- `qLDiagSqrtInv` is only required for the dual solvers. It is now computed as-needed rather than unconditionally.
- `mj_solveM2` now requires a new input array `sqrtInvD` which contains the square root of the inverse diagonal D (formerly saved in `qLDiagSqrtInv`).

PiperOrigin-RevId: 710805133
Change-Id: I0622d6a8da3882916824e9c10bad9223c122c321

src/engine/engine_print.c

@@ -1107,7 +1107,6 @@ void mj_printFormattedData(const mjModel* m, mjData* d, const char* filename,
   }
 
   printArray("QLDIAGINV", m->nv, 1, d->qLDiagInv, fp, float_format);
-  printArray("QLDIAGSQRTINV", m->nv, 1, d->qLDiagSqrtInv, fp, float_format);
 
   // B sparse structure
   printSparsity("B: body-dof matrix", m->nbody, m->nv, d->B_rowadr, NULL, d->B_rownnz, NULL,